Shaking screen



Aug. 3 1926. 1,594,854

' P. S. SAVAGE SHAKING SCREEN Filed July 31 1923 2 Sheets-Sheet 1Patented Aug. 3, 1926.

UNITED STATES PATENT OFFICE.

PHILIP S. SAVAGE, OF BUFFALO, NEW YORK, ASSIGNOR, BY DIRECT AND MESNEAS- SIGNMENTS, TO ROBINSOONVEYING- BELT COMPANY, A CORPORATION OF NEW'JEnsEY.

SHARING SCREEN.

Application filed July 31, 1923. Serial No. 654,849. 7

This invention relates to improvements in shaking screens designed moreespecially for the screening of coke or other coarse granular material.

The principal objects of the invention are to provide a screen in whichan improved shaking eifect is obtained, resulting in more certain andeffective separation of the coarser and finer particles, greater outputof work and less abrasion and wear of the screening grid; a suitabledegree of rapidity and amplitude of vibra-- tion is developed withoutthereby involving any liability of undue wear or racking; and thevibratory throw of the screen frame may be readily and certainlyregulated in order to best adapt the screen to the individualcharacteristics, e. g. weight,

consistency and form, of the particular material to be treated; andwhich isexceedingly simple in its organization, being devoid of anymechanism which is liable to de rangement or undue wear or, inconsequence of wear, to produce any failure or unevenness of action.

With the above objects in view the invention consists generally in thenovel combination and arrangement of the screen frame and the elementsconstituting its actuating and supporting means, the organization beingcharacterized by the mounting of the screen frame for pivotal movementabout its actuating means as an axis, and the provision of resilientmeans connected to said frame distant from said actuating which permitsof longitudinal vertical displacement of said frame and isself-synchronizing with reference to the action of said actuating means.

An embodiment of the invention is illus trated in the accompanyingdrawings, wherein Figure 1 is a plan view of the shaking screen. I

Figure 2 is a side elevation.

Figure 3 is a detail plan view of one of the spring supports.

Figure 4 is a side elevation of the same.

Figure 5 is a sectional view on the line 5-.5 of Figure 4.

at a point means and supporting as well as 1 is reciprocated preferablyconsists of ec centrics 3 mounted on a transverse operating shaft 4. Thesupporting frames 2 are provided with bearings 5 for the shaft 4 and theside bars of the frame 1 are provided with hearings or straps 6 in whichthe eccentrics 3 are journaled. The shaft 4 is arranged at a suitablepoint between the ends of the frame 1 and serves as a supporting elementfor said frame which is otherwise yieldingly supported at or near oneend from the frames 2 whereby it may rock about the eccentrics 8 as anaxis.

As shown, the frame 1 is yieldingly supported at its upper end, thesupporting means preferably comprising leaf springs 7 arrangedcantilever-wise and links or shackles 8 pendent from the free ends ofthe springs 7 and' pivoted at their lower ends to the side bars of theframe 1. The springs T are fitted in and project substantially to anequal extent from boxes 9 provided on the supporting frames'2 and ineach instance bear upon a shoulder 10 at the front of the box 9 andwhich forms the lower wall of the opening 11 through which the springprojects, the effective length of the springs being determined by theextent to which they project beyond the shoulders 10. Within the boxes 9the leaves of the springs are clamped together by upper and lower plates12 and 13 connected by bolt andnut fastenings 14. The plates 12 and 13also serve as hearing plates, the plate -13 engaging or seating upon thebottom of vides a bearing for an adjusting screw '19- through the upperwall of the box 9 and being held fast by lock nuts. The inner side walland the top Wall of each'box 9 is provided by an angle member 16 whichis secured by bolts 17 to the frame 2 and projects rearward from thebox- 9, at its-rear end being; formed with a web 18 which proby means ofwhich the position of the spring 7, and hence the extent to which saidspring PI'OJGCtS, may be regulated. The

screw 19 isprovided at its rear end with a hand wheel 20 a' nd at itsopposite end projects into the box 9 and is connected by a swivelcoupling 21 with the rear end of the spring 7. In the adjustment of thesprings 7 the. screws 15 are first backed off to relieve the pressure onthe springs and the screws 19 arethen manipulated to advance or retractthe springs 7 accordingly as the effective lengths of said sprin s areto be increased or decreased, after w ich the screws 15 are tightened inorder to secure the springs against displacement.

,In operation, as the screen frame is vibrated by the eccentrics it isalso caused by the springs 7 to rock about the eccentrics as an axis,whereby the vertical movements of the ends of the screen frame are inthe same directions at the same periods of operation and are preferablyof the same extent. However,'the upper or intake end of the screen framemay be caused to have elther a somewhat greater or a somewhat lessdegree of vertical vibration than the discharg end andeither of thesearrangementsmay occasionally be of advantage, according to'the existingconditions. The eccentrics may rotate either clockwise orcounter-clockwise according to choice as dictated by existingconditions, a clock-..

wise rotation of the eccentrics having the effect of accelerating theflow of aterial along the screen frame and "a coun r-clockwise rotationof the eccentrics having the effect of retarding the flow of materialalong the screen frame. The vertical vibrations of the screen frame havea peculiar snap or definiteness which is due to the action of thesprings 7 and has the effect of bouncing the material on the screeninggrid; that is to say, while the frame is ap-- preaching the end ofeachsucceeding stroke the springs are drawn forcibly down to a limitedextent by the pull of'the links thereon, but in the initial movement ofeach 'succeeding stroke the tension of the links on the springsis'relieved and in conse-1 links sharply rebound or snap upward in' amanner to impart the described vertical vibrations to the screen frame.A plurality of snapping vertical impulses are thus given to the frameduring each reciprocation thereof by the eccentric connection'. Therapidity and dequence the they are gree of the bouncing actions are suchthat they are effective in causing the discharge of the finer portionsof the material through the meshes of the screening grid. The workingcapacity of the screen is thus enhanced while at the same time the dragof the material on the screening grid is reduced to a minimum andconsequently there is a reduction-1 of the abrasive effect of thematerial on the screening grid so that the latter lasts longer and givesbetter service. The bouncing action described is of substantialadvantage in any case, for the reasons noted, but it is 'of particularadvantage where the material is in a somewhat damp or moist condition,whereby its particles tend to cohere.

The rapidity and extent of the vibrations are to be determined inaccordance with the characteristics of the material to be treated, thecoarser and heavier materials being more efiectively separated byvibrations of less frequency and greater amplitude and the lighter andfiner materials being more effectively separated by vibrations ofgreater frequency and less amplitude. The speed and diameter of theeccentrics are accordingly selected to meet the conditions of theparticular work for which the screen is intended and the springs 7 areadjusted whereby their action, due to their effective length, isco-ordinated to the action -of the eccentrics.

The eccentrics maybe located as desired along the length of the screenframe but preferably located about a third, more or less, of the totallength of the scfreen frame from-the discharge end there- 0 r Theoperation of the screen in any case has the characteristics abovepointed out. However, the particular action produced will depend uponthe co-relation' of several factors, viz.,v the location of theeccentrics along the length of the screen frame, the rapidity,j -throwand direction of rotation of the eccentrics fective length of thesprings 7; and consequently as regards the action of the screen acertain range of selection is available involving the selection andco-ordination of the factors above stated, whereby the engineer whodesigns the screen may best lar work for which it may be intended.

Having fully described my invention, I claim v 1. In a shaking screen,in combination, a screen frame, an operating eccentric about which saidframe may pivot and which participates in its support, and resili entsupporting means for 'said frame located at a distance from saideccentric, said means being constructed and arranged to impart aplurality of snapping vertica andthe strength and eflocated at adistance from said eccentric and connected to the upper end thereof,said means being constructed and .arranged to impart a plurality ofsnapping vertical impulses to the frame during each reciprocationthereof by the eccentric, and comprising a spring member and a linkconnection between said member and the frame.

3. In a shaking screen, in co mbination, a screen frame an operatingeccentric about which said frame may pivot and which participates in itssupport, and a leaf spring and. link connection supporting said frame ata distance from the eccentric.

4:. In a shaking screen, in combination, a screen frame, an operatingeccentric about which said frame may pivot and which participates in itssupport, a leaf spring arranged cantilever-wise, and a link connectingthe free end"of said'spring with the frame at a distance from theeccentric.

5. In a. shaking screen, in combination, a screen frame, an operatingeccentric about which said frame may pivot and which participates in itssupport, a leaf spring arranged cantilever-wise, a link connecting thefree end of said spring with the frame at a distance from the"ec--centric, and adjusting means for varying the effective length of saidspring.

6. In a shakingscreen, in combination, a screen frame, an operatingeccentric about which said frame niay pivot and which participates inits support, and resilient supporting means for said frame compris-.

ing a pair of leaf springs and links connecting said springs to. saidframe at points distant from said eccentric.

7. In a shaking screen, in combination, a screen frame, an operatingeccentric about which said frame may pivot and which participates in itssupport, resilient supporting means for said frame comprising a pair ofleaf springs arranged cantileverwise and links connecting the ends ofsaid springs to said frame at points distant from said eccentric.

, 8. In a shaking screen, in combination, a screen frame, an operatingeccentric about which said. frame may pivot and, which participates inits support, resilient supporting means for said. frame comprising apair of leaf springs arranged cantileverwise and links connecting theends of said springs to said frame at points distant from saideccentric, and adjustable means for varying the effective length of saidsprings. I

9. In a shaking screen, in combination, an inclined screen frame, anoperating cccentric about which said frame may pivot and whichparticipates in its support and resilient supporting means for saidframe comprising a pair of leaf springs arranged cantilever-wise andlinks connecting r the ends of said springs to said frame at points nearthe upper end thereof and distant from said eccentric.

10. In a shaking screen, in combination,

an inclined screen frame, an operating eccantilever-wise and linksconnecting the ends of said springs to said frame at points near theupper end {thereof and distant from said eccentric, and adjustable meansfor varying the effective length pf said springs.

. 11. In a shaking screen, in combination, a screen frame, an operatingecentric about which said frame may pivot, springmeans acting on saidframe in consequence of the operation of said eccentric to cause saidframe to rock relatively to said eccentric as an axis, and to impart aplurality of snapping vertical impulses to said frame during eachreciprocation thereof by the e0- centric, said means comprising a springmember and a link connection between said member and 'the frame, andadjustable means for modifying the action of said springsl 12. In ashaking screen, in combination,

a screen frame, means for yieldingly and ing a leaf spring arrangedcantilever-wise,

and a link connecting the free end of said spring with the frame, andactuating means pivotally connected to said frame at a distance fromsaid supported end and operating to reciprocate said frame.

13. In a shaking screen, in combination, a screen frame, actuating meanspivotally connected to said frame and operating to reciprocate the same,and resilient means acting upon said frame at a point dlstant from saidactuating means to cause said frame to rock aboutthe axis of its pivotalconnection with said actuating means during and in consequence of theoperation of said actuating means whereby the ends of said frame move inthe same vertical di- V rections at the same period of time, saidresilient means being constructed to impart a plurality of snappingvertical impulses to the frame during each reciprocation thereof.

14. hi a shaking screen, in combination, a screen frame, actuating meanspivotally connected to said frame and operating to reciprocate the same,resilient means acting upon said frame at a point distant from saidactuating means to cause said frame to rock about the axis of itspivotal connectlon with said actuatlng means during and in consequenceofthe operation of said actuating means whereby the ends of said framemove in the same vertical directions at the same period of time, saidmeans be ing constructed to impart a plurality of snapping verticalimpulses to the frame during each reciprocation thereof, and means foradjusting the tension of said resilient means.

In testimony whereof I aflix my signature.

PHILIP S. SAVAGE.

